Like you we love to try new things each trip! This next trip will be my 9yo's 19th Disney trip even though we live in Canada. We've already chosen some new things to try this trip and are excited about them!
I guess the question about value for staying the extra night at Disney vs flying home, to me would come down to what do I intend to do with the time I would normally be travelling home on the first day?
Let's say the flight home would be at 7pm therefore DME pickup at 4pm, leaving last park/Disney Springs at 2:30. What would I plan to do from 2:30 until bed that night?
If I'm going to be enjoying the parks or Disney Springs into the late evening then for me staying the extra night would be totally worth it!!! Making the most of every single moment we're there!
If I was more likely to head back to the resort early, pack up and just kinda be hanging out in the hotel room before bed then I'd take the flight home that evening as I wouldn't really be getting the fullest from my extra night there and I'd also have the next day home to begin unpacking, etc.
It really is personal choice. My dd and I are open to close park people and normally head home from Disney completely exhausted, almost needing a vacation after our vacation but with huge smiles on our faces and tons of new memories so it's totally worth it to us!
I hope this helps even a little. Bottom line is, what do you intend to do with the extra hours you've gained in the evening if you fly home the next day? I'd say stay and party on!!